Tethering device for airplanes



J. MARTIN TETHERING DEVICE FOR 'AIRPLANES May 10, 1949.

3 Sheets-Sheet 1 Filed July 31, 1945 Irma/0r May 10, 1949- .1. MARTINTETH ERING DEVICE FOR AIRPLANE S- 5 Sheets-Sheet 2 Filed July 21, 1945J. MARTIN TETHERING DEVICE FOR AIRPLANES May 10, 1949.

Filed- July 21, 1945 3 Sheets-Sheet 3 25 I'm/017 02 mam ir/w caV/o/myw.

UNITED STAT iQ'FFLCE TETHERING DEVICE FORAIRPLANES James Martin, HigherDenham, near Uxbridge, England Application July 21, 1945, Serial No.606357 In Great Britain August 7, 1944 5 Claims. (Cl.-2441l5) l .2.'This :invention relates? to tethering an aeroof.areoplanershowing"diagrammatically hOw -it TL'PIBJIELOXI thegroundwhilst the engine is being is tethered according to-thisinvention.

run for. testing or tuni purposes or during Pie- Fig. 2 is a perspectiveview of a cage for anchorir-zliminary running-up of the enginepreparatory ing in the ground andv provided with a socket oqtheaeroplane taking off from an aerodrome or 5 tadaptedto receive the basepillar.

thenplace. It is the usual practice when test- Fig. 3 isa'partrsectlonal .elevationvshowingsan s zing: or *runningmprthe engineof an areoplane ...alternative type of socket and also the base pillar112071312468 wooden or-..other checks in front of the and swivelplateforzthe tethering cables.

landing wheels of the aeroplane in order to pre- Fig. i is a perspectiveview ofsone of the undervent it from moving onthe ground owing to the icarriagelanding wheelsshowing how the tether- :wthrust. produced byrotation of the airscrew or ing cable ma b attached to its axle.

nairscrews. Owing to the steady increase of en- Fig, 5 is a partsectional planshowingythefors n power and t0 the reased thrust producedward end of the tethering cable securedto a by variable pitch andcontra-rotating airscrews, swivel plate on the endof-ztheiaxle'of'anvunder- ;.this method is no longer satisfactory andthis ap- 5 carriage landing wheel.

v-splies more parti ul y t oplanes of the high "Fig. 6 is a perspectiveview showing in detail xt'spe fighter type. It is found that there is an;.the base pillar withiconnections for thetwo :forszincreasinggtendenceyfor the aeroplane to jump 1ward1y extending tethering-cablesand theupg-thechocks when the engine is n p 3 wardly extending cable forconnection to the rear .thing like full throttle or maximum revolutions,end of the fuselage'of the aeroplane and includwith a conseq en n r ofdamage to the aer ing .means' for adjusting: the effective length of:-plane and of injury to the pilot or tester in the .the upwardlyextending cdb1e,,and

aeroplane and other mechanics or onlookers in Fi 7 i a detail showing analternative ad- .rgthe1neighborhcod. The object of this inventionjusting means for varying theeffective length ;-is toprovide a morereliable and positive method f the upwardlyextending cable.

::r.0f;:anchoring 0r et gi aeroplane 011 an -Referring to Fig. 1 of thedrawings the aero- -:aaerodrome or other place. plane l is tethered? by?two tethering cables. 2 izAccording, to this invention a single tetherinsecured at their forward endsto the axler-en'ds .memberis securely:ranchored and fixed in t of the landin wheels 3 of the undercarriage:iaerodrome; runway,- t sting shed or ot er p a 36 legs 4. The-dotanddashlines indicate alternaa swivelling connection is provided on thetethertivepositionsfor tetheringcables 2a which:may fling memberSecuring 011601 more Cables .be secured tothe undercarriage legs 4 oreven sadapted to be connected to forward parts of the higher up closetdth i m; of attachmentqto e opl ne to take the-forward thrust and afurthe wingsof the aeroplane. :The other. end-f rthenconnection from thetethe g member 35. the tetheringcables 2 or Zaare secured to a plate"ztending upw r ly to the tail end of t e aeroplane hichmay swivel aboutaqbase pillar secured in .ssto. restrain its. tendency tolift. It ispreferred k t 5 h ed in the ground by a, cages 0 provide a socket firmlya o in t rm into which it isbuilt. A further upwardly "BX- drome. orv oter .rpl e and a ase pillar is fitted tending. cable 'lvextends from thebase pillar in thereto. An attachment plate swive s ab ut t e sothesocket 5 andis connected to a fitting 8 secured b pillar and ttethering Cables are 0 :to a strongpartofthe fuselage frame. Ifhow-,nectedto .theiplateand are pr V ded at t e ever the fuselage is of.monocoque construction, forward ends with readily releasableconnections then the cable [may-be; connected to a sling 9 for securingto suitable parts of the aeroplane (shown in dotand 'dashrlines) whichis passed such as the landing wheel axles, the undercarround thefuselage. riage legs or the wings. These cables take the for- Theconstruction ofthe-cage 6. is ShOWll'llIl' Fig. ward; thrust when theengine is running and en- 2. This is intended primarily for anchoringthegable thetaeroplane to face in any direction round socket 5 in ordinaryopen ground 'such as a field :ythe tethering member. A link extendsupwardly or common or 'on desert orssandy beaches which from the basepillar, to a readily releasable conit is required to usees atemporary oremergency nector by which it is secured to the tail end of theaerodrome. The cage 6is built round a central aeroplane to control thelift thereof, and means tube lt-havingiflanges II at itstwo ends and thesmayibeprovided for adjustingthe efiective length socket 5 is fitted in=theupper end of the tube l 0. -:-;:of;th'e ,1ink. The cage comprisesupper and lower rectangular :f-In;:order .thatthe. inventionmay be moreread-. frames 52 and-l3 formed of angle'iron and conriily; understood,examples. showing how it may be heated to the flanges II at the .twoends of the carriedg..into...efiect willcnowibeu.described.withwtubexlll. by .zthe.radiahmembersijll. The .;two

reference to the accompanying drawings, in frames l2 and I 3 areconnected together by corwhich ner posts I5 and the whole structure isstifiened Fig. 1 is a perspective view of a fighter type by the diagonalstays It. The cage is of a suflicient size so that when a suitable holeis dug in the ground and the cage is placed in position in it and thematerial removed in digging the hole is again filled into it and firmlyrammed, then the cage will be so firmly secured that it will withstandthe maximum thrust or lift which could possibly be exerted on it by anyaircraft intended to be tethered thereto.

An alternative form of anchorage for the socket 5 is shown in Fig. 3.This arrangement is intended mainly for use in permanent aerodromes,runways or testing sheds and comprises a strong tube of any suitablelength which is set vertically in concrete 2! and has any suitablenumber of transverse rods 22 passed through the tube and projectinglaterally into the concrete so as to secure a firm anchorage of the tube23 in the concrete. The top of the socket 5 which is Welded into thetube 29 is preferably located in a shallow recess in the ground so thatthe base pillar 23 when fitted in the socket 5 does not project muchabove normal ground level. The base pillar 23 is provided with a shank2d the upper part of which is a close fit in the plain bore of thesocket 5 whilst the lower end of the shank 24 is screw threaded and isscrewed into the lower screw threaded part of the bore 25 in the socket5. The upper part of the base pillar 23 (shown also in Fig. 6) has ahexagonal part by which it may be screwed firmly into the socket 5. Onthe bearing 26 is fitted the swivel plate 2'! the bore 28 of which isradiused to allow the swivel plate to align itself with the tetheringcables 2. The tethering cables 2 are each fitted with a forked cable end29 the shank 30 of which is swaged onto the end of the cable and theforked end of each is pivoted to the swivel plate 21 by a pivot bolt 3|.The swivel plate 21 is retained in position by a collar 32 clampedagainst a shoulder 33 by a nut 34. The length of the bearing 26 isgreater than the thickness of the swivel plate 21 so as to permit theswivel plate to rock on the bearing 26 to a limited extent to line upwith the direction of pull on the cables 2.

On the top of the base pillar 23 are formed the two lugs 35 bored toreceive the pivot bolt 35 which passes through them and the block 31(see Fig. 6). To this block are secured the perforated links 38 by thepivot bolt 39 which passes through the block 3'! at right angles to thepivot bolt 36. The cable end fitting 40 of the cable I is securedbetween the links 38 by a pivot bolt which may be engaged with any pairof holes 42 in these two links 38 there-by providing a means ofadjusting the effective length of the cable 1. The upper end of thecable I is provided with a forked end fitting 43 which may be secured tothe eyebolt 8 which is fitted to a strong part of the fuselage frame ofthe aeroplane, or to the end of the sling 9 if the fuselage is ofmonocoque construction. This connection is made by the transverse pin 44having a cranked handle 45 to facilitate its insertion and removal. Fig.7 illustrates an alternative form of adjustment for the length of thecable 1 in which a double ended nut 46 engages with right and left handscrew threaded parts 41 and 48 secured to the cable 1 and the cable endfitting 40. Rotation of the double ended nut 46 will increase ordecrease the effective length of the cable '7 according to the directionof rotation in the well known manner.

The forward ends of the cables 2 are fitted with Iii forked end fittings50 which may be connected to anchorage plates 5| pivoted on the ends ofthe axles 52 of the undercarriage wheels 3 and secured by the nut 53 asshown in Figs. 4 and 5. The forked end fitting 50 may :be secured to theanchorage plate by a nut and bolt or preferably by a quickly releasablepin 54 having a cranked handle 55 similar to the pin 44 shown in Fig. 6for securing the upper end of the cable I.

In use the aeroplane is wheeled to a position over the tethering deviceand is turned into wind. The swivel plate 21 is turned round the basepillar 23 and the cable ends of the cables 2 are secured to theanchoring plates provided on the aeroplane by means of the connectingpins 54. The forked fitting 43 at the upper end of the cable I issecured to the eyebolt 8 or the sling 9 by means of the pin 44. Theengine of the aeroplane may then be started up and then run untilsuitably warmed after which any of the usual tests may be carried out.When completed the engine is throttled down and the securing pins 44 and54 may be removed and the aeroplane is ready to take off.

I claim:

1. A device for anchoring an aeroplane comprising a single tetheringmember adapted to be anchored to an aeroplane landing or storagesurface, said means comprising a socket, a pin mounted in said socket, acable having one end secured to said pin and the other end adapted to besecured to a forward part of an aeroplane to take the forward thrust, asecond cable having one end secured to said pin and the other endadapted to be secured adjacent the tail end of the aeroplane, said tailanchoring cable being shorter than said other cable whereby the socketis necessarily positioned adjacent the tail end of the aeroplane,thereby preventing the tail from rising.

2. An anchoring device as recited in claim 1 in which the socket isdisposed vertically in the center of an open work cage, and means tosecure said cage to said fixed landing or storage surface.

3. An anchoring device as recited in claim 1 in which said socket isprovided with a multiplicity of transverse projecting rods enabling itto be embedded in said landing or storage surface.

4. An anchoring device as recited in claim 1 in which said forwardextending cable is fixed to a collar surrounding said rotatable pin.

5. An anchoring device as recited in claim 1 in which the free ends ofsaid cables are provided with means for rotatably coupling them to partsof said aeroplane,

- JAMES MARTIN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS N umber Name Date 1,309,036 Knight July 8, 19192,333,559 Grady Nov. 2, 1943 2,383,950 Baliman Sept. 4, 1945 FOREIGNPATENTS Number Country Date 51,561 Germany Jan. 10, 1912 183,469 GreatBritain Oct. 11, 1923 334,509 Germany Mar. 14, 1921 418,479 France Dec.10, 1910 711,338 France June 23, 1931

